What is the film that was being made wthin this film...about cat men?

In this film, the two films "Cat Men" and "The Son of the Cat Men" were based on two actual films, both starring French actress Simone Simon:

The Cat People (1942)
http://www.imdb.com/title/tt0034587/

followed by
The Curse of the Cat People (1944)
http://www.imdb.com/title/tt0036733/

Cat People was probably the inspiration

This is an homage to the cat people movies made in the forties by Val Lewton and Jacques Tourneur.